I am/am not skiing
I'm skiing.
She is/isn't riding a bike.
She is riding a bike
She is/isn't cooking
She is cooking
He is/isn't playing football
He isn't playing football.
She is/isn't dancing
She isn't dancing
He is/isn't swinging.
He isn't swinging.
She is/isn't sleeping
She is sleeping
We are/aren't jumping hopscotch.
We aren't jumping
She is/isn't reading.
She isn't reading
They are/aren't fighting
They are fighting.